Can anyone explain this packet from 255.1.164.106 ??

[ajsouthard]

We are running a ping test and the pings are failing. When we "debug ip packet" we see packets from this "255.1.164.106" address that appear to be answering the ping that is failing. Has anyone seen this before ? Where could these packets be coming from ? The 255.x.x.x adress is not configured on any of our devices. The last octet decrements by 1 for each failed ping. See below

routerA#ping 10.129.1.5

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.129.1.5, timeout is 2 seconds:

Sep 20 09:19:35.887: IP: s=10.128.1.6 (local), d=10.129.1.5 (GigabitEthernet2/1)

, len 100, sending

Sep 20 09:19:35.887: IP: s=255.1.164.106 (local), d=10.128.1.6 (GigabitEthernet2

/1), len 8703, sending full packet.

Sep 20 09:19:37.887: IP: s=10.128.1.6 (local), d=10.129.1.5 (GigabitEthernet2/1)

, len 100, sending

Sep 20 09:19:37.887: IP: s=255.1.164.105 (local), d=10.128.1.6 (GigabitEthernet2

/1), len 8703, sending full packet

Sep 20 09:19:39.887: IP: s=10.128.1.6 (local), d=10.129.1.5 (GigabitEthernet2/1)

, len 100, sending

Sep 20 09:19:39.887: IP: s=255.1.164.104 (local), d=10.128.1.6 (GigabitEthernet2

/1), len 8703, sending full packet.

Sep 20 09:19:41.887: IP: s=10.128.1.6 (local), d=10.129.1.5 (GigabitEthernet2/1)

, len 100, sending

Sep 20 09:19:41.887: IP: s=255.1.164.103 (local), d=10.128.1.6 (GigabitEthernet2

/1), len 8703, sending full packet

Sep 20 09:19:43.887: IP: s=10.128.1.6 (local), d=10.129.1.5 (GigabitEthernet2/1)

, len 100, sending

Sep 20 09:19:43.887: IP: s=255.1.164.102 (local), d=10.128.1.6 (GigabitEthernet2

/1), len 8703, sending full packet.

Success rate is 0 percent (0/5)

routerA#un all

All possible debugging has been turned off

[dgahm · Accepted solution]

In terms of classful addressing 255 is class E, which is experimental, and rarely used.

The debug shows the source as local, meaning the router is originating the 255 packets. Can you trace to 255.1.164.102? Is it in the ARP table?

What network and mask is assigned to G2/1?

Can you post the router config? What model is it? What IOS?

Interesting problem!